﻿// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.

using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design.Serialization;
using System.Globalization;

namespace System.Windows.Forms;

public partial struct LinkArea
{
    /// <summary>
    ///  LinkAreaConverter is a class that can be used to convert LinkArea from one data type
    ///  to another. Access this class through the TypeDescriptor.
    /// </summary>
    public class LinkAreaConverter : TypeConverter
    {
        /// <summary>
        ///  Determines if this converter can convert an object in the given source
        ///  type to the native type of the converter.
        /// </summary>
        public override bool CanConvertFrom(ITypeDescriptorContext? context, Type sourceType)
        {
            if (sourceType == typeof(string))
            {
                return true;
            }

            return base.CanConvertFrom(context, sourceType);
        }

        /// <summary>
        ///  Gets a value indicating whether this converter can convert an object to the
        ///  given destination type using the context.
        /// </summary>
        public override bool CanConvertTo(ITypeDescriptorContext? context, Type? destinationType)
        {
            if (destinationType == typeof(InstanceDescriptor))
            {
                return true;
            }

            return base.CanConvertTo(context, destinationType);
        }

        /// <summary>
        ///  Converts the given object to the converter's native type.
        /// </summary>
        public override object? ConvertFrom(ITypeDescriptorContext? context, CultureInfo? culture, object value)
        {
            if (value is string valueStr)
            {
                ReadOnlySpan<char> text = valueStr.AsSpan().Trim();
                if (text.IsEmpty)
                {
                    return null;
                }

                // Parse 2 integer values.
                culture ??= CultureInfo.CurrentCulture;
                Span<int> values = stackalloc int[2];

                if (!TypeConverterHelper.TryParseAsSpan(context, culture, text, values))
                {
                    throw new ArgumentException(
                        string.Format(
                            SR.TextParseFailedFormat,
                            valueStr,
                            "start, length"));
                }

                return new LinkArea(values[0], values[1]);
            }

            return base.ConvertFrom(context, culture, value);
        }

        /// <summary>
        ///  Converts the given object to another type. The most common types to convert
        ///  are to and from a string object. The default implementation will make a call
        ///  to ToString on the object if the object is valid and if the destination
        ///  type is string. If this cannot convert to the destination type, this will
        ///  throw a NotSupportedException.
        /// </summary>
        public override object? ConvertTo(ITypeDescriptorContext? context, CultureInfo? culture, object? value, Type destinationType)
        {
            if (value is LinkArea pt)
            {
                if (destinationType == typeof(string))
                {
                    culture ??= CultureInfo.CurrentCulture;

                    string sep = culture.TextInfo.ListSeparator + " ";
                    TypeConverter intConverter = TypeDescriptor.GetConverter(typeof(int));
                    string?[] args =
                    [
                        intConverter.ConvertToString(context, culture, pt.Start),
                        intConverter.ConvertToString(context, culture, pt.Length)
                    ];
                    return string.Join(sep, args);
                }
                else if (destinationType == typeof(InstanceDescriptor))
                {
                    return new InstanceDescriptor(
                        typeof(LinkArea).GetConstructor([typeof(int), typeof(int)]),
                        new object[] { pt.Start, pt.Length });
                }
            }

            return base.ConvertTo(context, culture, value, destinationType);
        }

        /// <summary>
        ///  Creates an instance of this type given a set of property values
        ///  for the object. This is useful for objects that are immutable, but still
        ///  want to provide changable properties.
        /// </summary>
        public override object CreateInstance(ITypeDescriptorContext? context, IDictionary propertyValues)
        {
            ArgumentNullException.ThrowIfNull(propertyValues);

            try
            {
                return new LinkArea(
                    (int)propertyValues[nameof(Start)]!,
                    (int)propertyValues[nameof(Length)]!);
            }
            catch (InvalidCastException invalidCast)
            {
                throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), invalidCast);
            }
            catch (NullReferenceException nullRef)
            {
                throw new ArgumentException(SR.PropertyValueInvalidEntry, nameof(propertyValues), nullRef);
            }
        }

        /// <summary>
        ///  Determines if changing a value on this object should require a call to
        ///  CreateInstance to create a new value.
        /// </summary>
        public override bool GetCreateInstanceSupported(ITypeDescriptorContext? context) => true;

        /// <summary>
        ///  Retrieves the set of properties for this type. By default, a type has
        ///  does not return any properties. An easy implementation of this method
        ///  can just call TypeDescriptor.GetProperties for the correct data type.
        /// </summary>
        [RequiresUnreferencedCode(TrimmingConstants.TypeConverterGetPropertiesMessage)]
        public override PropertyDescriptorCollection GetProperties(ITypeDescriptorContext? context, object value, Attribute[]? attributes)
        {
            PropertyDescriptorCollection props = TypeDescriptor.GetProperties(typeof(LinkArea), attributes);
            return props.Sort([nameof(Start), nameof(Length)]);
        }

        /// <summary>
        ///  Determines if this object supports properties. By default, this is false.
        /// </summary>
        public override bool GetPropertiesSupported(ITypeDescriptorContext? context) => true;
    }
}
